If you are familiar with the Everygamegoing site, you will see this API call demonstrated when a logged-in user performs any search. The
results displayed show whether the user already owns a copy of any item in the search results by displaying its cover scan (black and white indicates he
does not own it, colour indicates that he does own it). Clicking on the item's cover art brings up a pop-up menu, the first button being
'Add To Collection' or 'Remove From Collection' as appropriate. This API command is called when that button is clicked.

Simple Usage To Toggle By Sales Item

Alternatively, you may toggle items in your collection by the unique sales_item_id. This is useful if you have more than one copy of the same item in your
collection:

If you are the owner of sales_item_id 563 and wish to remove it from your collection, then call: